Page 100 - ΝΑΥΤΙΚΑ ΧΡΟΝΙΚΑ - ΜΑΙΟΣ 2023

GREEN SHIPPING

involves cooling the flue gas to focusing on CO₂ absorption by utilizing
extremely low temperatures, typ- chemicals to trap the CO₂ , then releas-
ically below -78 degrees Celsius, ing it storing it in liquid or solid form.
where CO₂ can be condensed and Carbon capture could be anything from
separated. The process relies on 30 % to 100 % in order to meet the
the different boiling points of CO₂ statutory requirements of keeping the
and other gases in the flue gas CO₂ trading costs low. One MT of fuel
mixture. By cooling and pressuriz- will be generating more than 3.2 MT of
ing the flue gas, CO₂ can be cap- CO₂ excluding the additional fuel that
tured and subsequently released will have to be consumed during the
by reducing the pressure. Cryo- carbon capture and storage process.
genic separation is energy-in- Apart from the use of amines, one of
tensive but has the advantage of the most promising technologies is CO₂
producing a relatively high-purity absorption using Ammonium hydroxide.
CO₂ stream. In this process, the flue gas contain-
Carbon capture technology onboard ing CO₂ is passed through an absorber
ships is a developing field; more than column where it comes into contact
30 companies (many of them spon- with a stream of NH₄OH solution. The
sored by Green funds available from CO₂ reacts with NH₄OH to form ammo-
their national governments) are now nium bicarbonate (NH₄HCO₃), which is
trying to develop and test onboard then separated from the solution. The
CCS systems that will enable to cap- solution is then regenerated by heating
ture and store CO₂ at economically it, which releases the CO₂ and water
Capacity of large-scale CO2 capture competitive costs in relation to carbon vapor, leaving the NH₄OH to be reused
projects, current and planned vs. trading. From the several methods indi- for further CO₂ absorption. The CO₂
the Net Zero Scenario, 2020-2030
cated above, most of the vendors are is stored as powder of CaCO₃ which
according to a research carried out by
1400 the Korean government can be dumped
directly into the sea.

Currently, according to data retrieved
1200 from the International Energy Agency
(IEA), there are about 35 commercial
facilities applying CCUS (carbon cap-
ture, utilization, and storage) in indus-
1000 trial processes, fuel conversion, and
power generation, with a combined
annual CO₂ capture capacity of nearly
45 million metric tons. Although CCS
800 projects have not been utilized in a
large scale in the past, it is today gain-
ing significant momentum with approx-
imately 300 projects in various stages
600 of development. Over 200 new capture
facilities have been announced to be
operational by 2030, with the ability
to capture over 220 million metric tons
400 of CO₂ per year. For 2050 the Inter-
national Energy Agency (a UN body)
is expecting that more than 1.3 billion
tones originating from the use of fossil
200 fuels and other industrial processes
will be still be polluting the atmo-
sphere and will have to be captured,
0 transported and stored. This may gen-
2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 erate the need of operating a large
number of liquid CO₂ carrying ships.

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